Screen



K. R. BIXBY Jan. 3, 1939..

SCREEN Filed Oct.- 15, 1935 Y TN TX N/ EB Wm hi5 ATTUE'NEK Patented Jan. 3, 1939 UNITED STATES PATENT OFFICE SCREEN Application October 15, 1935, Serial No. 45,046

4 Claims.

This invention relates to a screen and more particularly to a screen adapted for use with coarse heavy material having severe abrasive action, such as coal, and the present screen is designed primarily as a dewatering screen to remove Water and small pieces of coal from a mass of coal which has been washed.

Screens heretofore used for this purpose have, for the most part at least, been quite expensive in construction and of short life. Inasmuch as it is desirable that the Walls of the screen openings should diverge downwardly to permit the free passage of fine material through the same, it follows that the wearing away of the upper parts of the screen material progressively increases the size of the openings, thereby permitting the passage of pieces of coal of sizes larger than that for which the screen was intended.

One Object of the present invention is to provide a simple efficient screen which will have long life.

To this end it is a further object of the invention to provide a screen of such a construction that the screening material may be worn away for a very substantial portion of its thickness without affecting the size of the screen openings.

A further object of the invention is to provide such a screen in which there will be little tendency for fine material to lodge in the screen openings and clog the same.

A further object of the invention is to provide such a screen which may be easily produced at a relatively low cost.

A further object of the invention is to provide such a screen in which the material supporting members will be shaped to provide a highly efficient dewatering action.

Other objects of the invention may appear as the same is described in detail.

In the accompanying drawing Fig. 1 is a plan view of a screen embodying my invention; Fig. 2 is a section taken on the line 22 of Fig. 1; and Fig. 3 is an edge View of the screen shown in Fig. 1.

In the drawing I have illustrated one embodiment of my invention and have shown the same as comprising a single screen element which may be of any suitable shape but is shown as flat in form. The screen as a whole may consist of a single screen element, as shown, or a plurality of such screen elements may be combined to provide the screen with a larger screening surface. This screen element, either alone or in combination with other similar elements, is usually supported in an inclined position by suitable mechanism, not here shown, which will impart thereto a vibratory movement as the material to be screened moves over the same.

Each screen element, which, as has been stated,

is complete in itself, comprises a plurality of elongate parts or screening members which are arranged side by side and spaced predetermined distances one from the other throughout their length. The several parts are rigidly secured one to the other and supported in their proper relative positions by connecting members which are rigidly secured to those sides thereof opposite the material receiving sides. The rods may be of any suitable character but preferably they are of such cross sectional shape that substantial portions thereof may be worn away by the abrasive action of the material without varying the width of the spaces between adjacent parts. For this purpose I prefer that the elongate parts shall be substantially round in cross section and they may conveniently consist of a plurality of round rods 5 arranged side by side and spaced short distances apart, the size of the rods and the spacing thereof being determined in part by the char acter of the material to be screened and the size of the fragments or particles which are to be permitted to pass through the spaces or screen openings. When the screen is used as a dewatering screen it is desirable to permit only very fine pieces or thin slivers of the coal to pass through the screen and usually the spaces or slots between the rods are quite narrow. In one installation the rods are approximately threesixteenths of an inch in diameter and are spaced apart one-thirtysecond of an inch.

The supporting members which connect the rods one to the other may be of any suitable character and are here shown as bars 6 which extend transversely to the rods beneath the same and preferably have direct contact with the lower 1 sides of the rods. It is preferable that the supporting bars be of such cross sectional shape that the sides thereof adjacent to the slots between the rods shall diverge downwardly so as to ofier but little obstructions to the passage of fragments or slivers of material through the slots adjacent to the bars. When the supporting bars are so shaped there is little tendency for the slivers or small pieces of coal or the like to lodge between the rods adjacent to the bars and thus clog the screen openings. In the present. construction'I have employed supporting bars which are round in cross section as such bars not only provide the necessary clearance about the same but are inexpensive and are easily handled in the manufacture of the screen. The supporting bars are here shown as round throughout their length.

The screen rods 5 may be of any suitable material but preferably they are formed of hard steel which is highly resistant to the abrasive action of coal or the like, and when the screen is to be used for screening Wet material a noncorrosive steel may be used. The rods being substantially round the shortest distance between adjacent rods is a point midway between the upper and lower surfaces thereof and consequently the upper portions of the rods may wear away for half the diameters of the rods without increasing the width of the spaces between the rods. Further, round rods can be secured at a lower cost than rods of special shapes and therefore their use reduces the cost of manufacturing the screen. These rods may be secured to the supporting bars in any suitable manner but it is desirable that the securing means shall be of such a character that it will not project beyond the sides of the respective rods so as to obstruct the slots, and also that it shall not extend above the rods so as to interfere with the free movement of the material over the same. The shapes of the rods and of the supporting bars are such as to provide contacts between the same of relatively small area and by spot welding the rods to the bars at these points of contact a strong rigid connection may be effected at small cost which will offer no obstruction to the passage of the material over the rods or the passage of fine material between the rods and about the bars and, further, such a connection does not weaken either the rods or the bars.

For the purpose of imparting a highly efficient dewatering action to. the screen I have, in the present instance, so shaped the rods 5 that they will be more or less tortuous in character and will not provide straight guides for the material 5 ,;efiicient dewatering action with only a slightly decreased capacity. In the construction shown each rod has adjacent portions bent laterally in opposite directions so that the adjacent parts of the rod, as shown at I, extend obliquely to the length of the screen in difierent directions, thereby: imparting to the rod a zigzag shape. The corresponding portions of adjacent rods are substantially parallel one with the other and the rods are spaced apart throughout their length so that the slots between the same while having a tortuous shape are unobstructed. The lateral deformation of the rods results in the formation of recesses in the respective sides of the screen between the outwardly diverging portions of the outermost rods and in order that the screen may be of uniform width throughout its length these recesses may be provided with fillers 8. The fillers may be of any suitable character but are here shown as sections of round rod each having one side thereof cut away to impart a substantially triangular shape to each section, when viewed from above. These fillers are rigidly secured to the supporting bars 6, by welding or otherwise, but in order to more firmly support the same I have arranged between adjacent supporting bars 6, along the respective sides of the screen, a plurality of short bars 9 which are rigidly secured at their ends, by welding or otherwise, to the respective supporting bars 6 and the end portions of the fillers 8 are welded to these short bars.

It will be apparent from the foregoing description that as the coal or other material moves over the screen the water and very fine material will be separated therefrom and pass through the openings or slots and that due to the unobstructed character of the slots, and the character of the supporting bars, there will be little tendency for the fine material to lodge in the slots and clog the same. The tortuous character of the rods causes the same to so act on the material as to break the surface tension of the water adhering thereto and thus facilitate the separation of the water from the material. The screen will have a long useful life because of the fact that large portions of the screen rods may be worn away without varying the width of the slots. Further, it will be apparent that the construction is of such a character that the screen may be manufactured at a relatively low cost.

While I have shown and described one embodiment of my invention, I wish it to be understood that I do not desire to be limited to the details thereof as various modifications may occur to a person skilled in the art.

Having now fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a screen of the character described, a plurality of round rods extending lengthwise of said screen and arranged side by side in spaced relation to receive the material to be screened, each rod having adjacent longitudinal portions in angular relation one to the other, and a plurality of bars extending transversely to and rigidly secured to the lower sides of said rods, short bars extending lengthwise of said screen at the respective sides thereof and arranged between and rigidly secured to adjacent transverse bars, and fillers arranged between outwardly diverging portions of the outermost rods at each side of said screen and rigidly secured to the respective short bars.

2. In a screen of the character described, a plurality of rods arranged side by side in spaced relation one to the other to receive the material to be screened, each rod having adjacent portions extending obliquely to the length of the screen and in different directions, the corresponding portions of the several rods being substantially parallel one with the other and the .spaces between adjacent rods being unobstructed throughout their length, and a plurality of bars extending transversely to and rigidly secured to the lower sides of said rods, said rods and said bars having contacting surfaces of small area.

3. In a screen of the character described, a plurality of round rods extending lengthwise of said screen and arranged side by side in spaced relation to receive the material to be screened, each rod having adjacent longitudinal portions in angular relation one to the other and the spaces between adjacent rods throughout their length, and a plurality of bars extending transversely to the lower sides of said rods and having narrow upper surfaces engaging said rods and rigidly secured thereto at their points of contact therewith.

4. In a screen of the character described, a plurality of round rods extending lengthwise of said screen and arranged side by side in spaced relation to receive the material to be screened, each rod being bent laterally to zigzag form, the several rods being substantially parallel one with the other and the spaces between adjacent rods being unobstructed, throughout their length, and a plurality of round bars extending transversely to and rigidly secured to the lower sides of said rods at their points of contact therewith.

KENNETH R. BIXBY.

being unobstructed 0 

